Linked Life Data

12117464

Source:http://linkedlifedata.com/resource/pubmed/id/12117464

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-7-15
pubmed:abstractText
Phosphogypsum (PG, CaSO(4).H(2)O), a solid byproduct of phosphoric acid manufacturing, contains low levels of radium ((266)Ra), resulting in stackpiling as the only currently allowable disposal/storage method. PG can be stabilized with class C fly ash and lime for potential use in marine environments. An augmented simplex centroid design with pseudo-components was used to select 10 PG:class C fly ash:lime compositions. The 43cm(3) blocks were fabricated and subjected to a field submergence test and 28 days saltwater dynamic leaching study. The dynamic leaching study yielded effective calcium diffusion coefficients (D(e)) ranging from 1.15 x 10(-13) to 3.14 x 10(-13)m(2)s(-1) and effective diffusion depths (X(c)) ranging from 14.7 to 4.3mm for 30 years life. The control composites exhibited diametrical expansions ranging from 2.3 to 17.1%, providing evidence of the extent of the rupture development due to ettringite formation. Scanning electron microscopy (SEM), microprobe analysis showed that the formation of a CaCO(3) on the composite surface could not protect the composites from saltwater intrusion because the ruptures developed throughout the composites were too great. When the PG:class C fly ash:lime composites were submerged, saltwater was able to intrude throughout the entire composite and dissolve the PG. The dissolution of the PG increased the concentration of sulfate ions that could react with calcium aluminum oxides in class C fly ash forming additional ettringite that accelerated rupture development. Effective diffusion coefficients and effective diffusion depths alone are not necessarily good indicators of the long-term survivability of PG:class C fly ash:lime composites. Development of the ruptures in the composites must be considered when the composites are used for aquatic applications.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0304-3894
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
93
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
167-86
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Stabilization of phosphogypsum using class C fly ash and lime: assessment of the potential for marine applications.
pubmed:affiliation
Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803, USA. krusch@lsu.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't